In a backlight source system of a liquid crystal display device, a vacuum infusion (VIF) process can be used to fabricate an array substrate. A sealant adopted in the VIF process is a mixture which contains epoxy resin as the main component and is further mixed with specific diluents. The sealant generally has a viscosity of 20-50 Pa·s, contains nonvolatile matter of 70%-90% by weight, and has a curing duration of 80-180 seconds at 150° C. Namely, it is necessary to perform thermal curing on the sealant during assembling.
In the VIF process, due to the design of a thermal pressing apparatus, a soft rubber cushion is applied over and under a substrate to be assembled (e.g., a glass plate) for thermal pressing, so that the sealant is cured upon reaching a specified width. During production of a liquid crystal display device with ball spacers, ball spacers are arranged uniformly between two glass plates to be assembled and up to edges of the glass plates. Once the two glass plates are assembled, a gap remains between glass plates for discharging gas in the panel during assembling, so that the frame seal will not suffer from obvious sealing defects in a thermal pressing process. These defects primarily comprise seal brush and seal narrow.
However, when a liquid crystal display device with post spacers (PS) is subject to the thermal pressing process, even the liquid crystal display device is provided with dummy PS and conventional process dummy seal, defects like seal brush and seal narrow still occur in the VIF process. The main reasons follow. In the process for forming post spacers, the color film (C/F) substrate is subject to an edge bead removal (EBR) process, in which the redundant sealant at a peripheral region of the glass plate is removed. After the process of dummy PS is completed, no sealant remains in an area at a distance of about 1 cm from the edge of substrate. In the thermal pressing process, the edge of the substrate is pressed airtight completely during assembling, so that the gas between two assembled glass plates can not be discharged, thus resulting in seal brush and seal narrow.